Q & A Library

Print this page | Sign up for free e-bulletins
 | Bookmark This Page

Is Echinacea a Dangerous Cold Remedy?
I heard recently that taking echinacea can pose a cancer risk. Is this true?
Answer (Published 3/8/2007)

Echinacea, a traditional herbal remedy prepared from the root and leaves of the purple coneflower, Echinacea purpurea and related species, stimulates the immune system and is used to prevent and treat common colds and other minor infections. The recommended adult dose is two capsules of freeze-dried extract four times a day or one teaspoon of the tincture in a little warm water at the same frequency. People also take echinacea to enhance immunity in the absence of infection - for this purpose, half the usual dose is sufficient.

Related Weil Products
Dr. Weil's Vitamin Advisor for Your Personal Care - Thousands of people have benefited from Dr. Weil's supplement recommendations, designed to complement your lifestyle and optimize your health. Learn more, and get your free, personalized Dr. Weil's Vitamin Advisor Recommendation today.

You probably heard about findings from a small study at the University of Arkansas that looked at the effect of echinacea on the digestive tract. To my knowledge, this is the first published research on this subject. The investigators gave daily doses of echinacea to 15 healthy adults and tested stool samples from before the study began, and then again 10 days and 17 or 18 days later. They found an increase in levels of both aerobic and anaerobic bacteria (those that grow in an oxygen-free environment.)

Most of the bacteria normally found in the colon are anaerobic, of which the Bacteroides group plays a major role. One of these strains, B. fragilis can cause disease under certain conditions, especially when intestinal flora changes quickly as a result of taking antibiotics. Previous research showed that a particular type of B. fragilis may play a role in inflammatory bowel disease and diarrhea and, the researchers noted, higher than normal concentrations of Bacteroides have been reported in people at high risk for colon cancer.

While interesting, these findings will have to be confirmed by larger studies before we can say whether echinacea poses any real risk of GI disease. The Arkansas researchers cautioned that "prolonged consumption" could prove deleterious to bacteria in the gastrointestinal tract, particularly for those who are ill. They noted that Germany's Commission E suggests using echinacea for no longer than eight weeks. For best efficacy, I suggest limiting continuous use of echinacea to no more than 10-14 days to treat colds and other minor infections. I do not use it as a long-term immunity enhancer; there are better botanicals for that, such as astragalus. Based on what we know now, I doubt that short-term use of echinacea is harmful to the GI tract or is a contributor in any way to colon cancer.

Andrew Weil, M.D.

Creative Commons License Some Rights Reserved Creative Commons Copyright Notice
A portion of the original material created by Weil Lifestyle on (specifically, all question and answer-type articles in the Dr. Weil Q&A Library) is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 United States License.

The Weil Vitamin Advisor
Get your FREE personalized vitamin recommendation & supplement plan today!

Dr. Weil on Healthy Aging
Your Online Guide to the Anti-Inflammatory Diet. Start eating for your health - begin your free trial now.

Dr. Weil's Spontaneous Happiness
Achieve emotional well-being in just eight weeks! Start your 10-day free trial now!

Vitamin Library
Supplement your knowledge with Dr. Weil's essential vitamin facts. Learn why they are necessary and more.

Dr. Weil's Optimum Health Plan
Your 8-week plan to wellness.
Begin your journey today!

Dr. Weil's Head-to-Toe Wellness Guide
Your guide to natural health.
Use the Wellness Guide today!

Dr. Weil's Anti-Inflammatory Diet
Food Pyramid

Our interactive tool can help improve overall health through diet.

Condition Care Guide
Learn about health conditions from acne to vertigo, and Dr. Weil's view of the best treatment options for each.

Healthy Recipes
Discover a treasure trove of healthy, healing foods and creative, delicious ways to prepare them.

Q&A Library
Over 2,000 questions from you and their corresponding answers from Dr. Weil.

Copyright © 2015 Weil Lifestyle
Information on this web site is provided for informational purposes only and is not intended as a substitute for the advice provided by your physician or other healthcare professional. You should not use the information on this web site for diagnosing or treating a health problem or disease, or prescribing any medication or other treatment.

Ad Choice
Advertising Notice

This Site and third parties who place advertisements on this Site may collect and use information about your visits to this Site and other websites in order to provide advertisements about goods and services of interest to you. If you would like to obtain more information about these advertising practices and to make choices about online behavioral advertising, please click here